Vulnerability · Published Apr 22, 2026 · Assigned by OX
CVE-2026-33601Insufficient validation of zonemd record
Medium 4.4
In plain English
A medium-severity null pointer dereference in Recursor from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)4.4Medium
Exploit odds (30 days)0.5%top 56.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
If you use the zoneToCache function with a malicious authoritative server, an attacker can send a zone that result in a null pointer dereference, caused by a missing consistency check and leading to a denial of service.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | pdns-recursor | 5.3.6-r0 | ALPINE-CVE-2026-33601 |
| Alpine:v3.24 | pdns-recursor | 5.4.1-r0 | ALPINE-CVE-2026-33601 |
| Debian:12 | pdns-recursor | no fix listed | DEBIAN-CVE-2026-33601 |
| Debian:13 | pdns-recursor | 5.2.9-0+deb13u1 | DEBIAN-CVE-2026-33601 |
| Debian:14 | pdns-recursor | 5.4.1-1 | DEBIAN-CVE-2026-33601 |
| Ubuntu:24.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33601 |
| Ubuntu:25.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33601 |
| Ubuntu:26.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33601 |
| Ubuntu:26.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33601 |
Affected products (as reported)
Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H